Automatic icemaker



United States Patent "ice 3,388,560 AUTOMATIC ICEMAKER William C.Moreland H, Export, Pa., assignor to Westinghouse Electric Corporation,Pittsburgh, Pa., a corporation of Pennsylvania Filed May 9, 1967, Ser.No. 637,232 6 Claims. (Cl. 62353) ABSTRACT OF THE DISCLOSURE Ice cubemaking apparatus of the character in which ice cube pockets in aflexible wall liner are inverted by pressurizing the space underlyingthe liner to eject frozen cubes therefrom, and having a gas pumpingsystem operable to obtain pre-release of the cubes from the pockets bydrawing the pockets down out of adherence with the cubes prior toinversion of the pockets.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to the art of ice cube making, and particularly to that categoryof the art dealing with apparatus in which a flexible Wall,pocket-forming liner in which the cubes are frozen is associated with asystem for inverting the pockets to eject the cubes, and returning thepockets to their water-receiving conditions.

DESCRIPTION OF THE PRIOR ART Pressure actuated, invertible pocket,automatic icernakers are known in the patent art. Typically, so far as Iknow, the pressurizing fluid pumped into and out of the space formedbetween the liner and the underlying tray has been a liquid such as asolution of glycerine and water. In one arrangement of this generalcharacter, as exemplified by that taught in U.S. Patent No. 2,770,102,the solution is stored in a reservoir adjacent the ice tray (i.e. withinthe freezing zone) so that when it is pumped into the space between theliner and tray for inverting the liner its low temperature does notintroduce undesirable heat into the system.

In another system, such as that exemplified by U.S. Patent 2,918,803,the ejecting liquid is stored in a region of substantially higherambient temperature than the temperature within the freezing zone andthe heat in the ejecting liquid is used to reset a thermal element toeflect a next succeeding filling operation after the ejection.

In still other arrangements of the invertible pocket or mold type, andas exemplified by U.S. Patent 2,969,651, mechanical means is used toscavenge the cubes sticking to the inverted molds during the ejectionoperation.

Automatic icemakers of the invertible mold type have not reachedcommercial fruition so far as I know. Perhaps the complexities inherentin using a liquid system for controlling the condition of the flexibleliner are a factor. Another factor may be the difficulties of insuringthe release of the cubes from the pockets during ejection.

SUMMARY OF THE INVENTION In accordance with my invention, a gas pumpingsystem is preferably used and is employed to obtain a pre-release, to adegree at least, between the cubes and the pockets before the cubes areejected by inversion of the pockets. This pre-release is believed to bemore practically achieved with a gas system than with a liquid system,

Patented June 18, 1958 although the latter may be used within the scopeof the invention. Additionally other problems inherent with a liquidsystem, such as close requirements of the volume of the ejecting charge,are substantially avoided. Other advantages of an arrangement accordingto my invention will be appreciated from the detailed description tofollow.

DRAWING DESCRIPTION IGURE 1 is a schematic illustration of one automaticicemaker according to my invention;

FIG. 2 is a schematic illustration of a modified arrangement of anautomatic icemaker according to the invention;

FIG. 3 is a fragmentary vertical sectional view through the traystructure for one pocket; and

FIG. 4 is a fragmentary isometric view of a tray and pocket structure ofanother character.

FIG. 1 embodiment In the drawing, the freezer compartment of a domesticrefrigerator, for example, is indicated by the dash-line outline 10. Theflexible wall, pocket-forming liner 12 overlies the rigid tray 14 and isattached along its peripheral edges to the peripheral edges of the trayso that the space generally designated 16 between the liner and tray issealed. The pockets 18 of the liner having a normal water-receivingcondition in which they are generally concave in section as shown by thesolid lines, and an inverted convex configuration as shown by the dashlines when the plenum space 16 is pressurized to push the pocketsupwardly.

The water supply means for the tray includes a water line 20 having an-on-off fill valve 22 and preferably a flow regulator 24 to compensatefor pressure variations in the water supply source.

The gas pumping system is powered by an electric motor 26 which, asdiagrammatically shown, drives a reciprocating diaphragm pump 28 throughthe motor shaft 36. The pump 28 may be of the well-known type in which aflexible diaphragm is flexed back and forth to produce volumetricchanges in a chamber, with a check valve in each of the ports to whichthe pneumatic lines 32 (outlet) and 34 (inlet) are connected to thepump. It is here noted that while the preferred pumping system ischaracterized as a gas system, to distinguish it from a liquid system,the gas may be reasonably dry air.

The air lines 32 and 34 are connected to a threeposition control valve36 which is positioned in accordance with the actuating cam 38 mountedon shaft 40 of the gear reducer 42 which in turn is driven by the motor26. The valve 36 may be of the character having an interior slide memberprovided with a number of passages for making selective connectionsbetween the various ports of the valve in accordance with the interiorposition of the slide controlled by the rotated position of cam 38. Thevarious connections made during a cycle of the operation will bedescribed in detail after the other components of the arrangement areidentified.

The air line 4 connects the valve 36 to the space 16 between the linerand tray, the air line 46 connects the control valve to the water fillvalve 22 to actuate it in accordance with the cycle stage, and the airline 48 connects the control valve to a flexible Wall bladder 50 whichserves as a variable voiume reservoir for the air charge. The air linesand the Components which they connect are sealed with respect toatmosphere.

The electrical component part of the arrangement includes a thermostaticswitch 52 and a physically proximate resistance heater 54, a cycleswitch 56 controlled by cam 58 on shaft of the gear reducer, and abucket switch 68 responsive to the quantity of ice produced andoperative in known fashion to terminate further cycling of the icemakerwhen a predetermined quantity has been harvested. The thermostaticswitch 52 and cycle switch 56 are in parallel as shown by the electricaldiagram so that if either of the switches are closed the seriesconnected heater 54 and motor 26 are energized if bucket switch 60 isclosed.

The thermostatic switch 52 is operative to open in response to heatproduced by the energized heater 54, and subsequently to close, with theheater off, in response to a cold condition corresponding to thatindicating the cubes are solidly frozen. Thus, the switch 52 and heater54 may be located in such a partly enclosed chamber within the freezingchamber 10 that there is a correlation between the rate at which the icecubes freeze and the rate at which the switch cools, after being heated,for a given freezer space temperature. Alternatively, the switch andheater may be positioned in the space 16 between the liner and tray toprovide a closer correlation of the freezing rate and the response rateof the switch.

The cycle is initiated, when the cubes are frozen, by thermostaticswitch 52 closing. The cycle is terminated, after the cubes have beenejected and the liner 12 brought back to a water receiving condition andfilled, by the opening of cycle switch 56 with the thermostatic switch52 also being open from the heater 54 energization.

Before detailing a cycle of operation of the iccrnaker, the function ofcam 58 controlling cycle switch 56, and cam 38 controlling valve 36 willbe briefly described. The cam 58 has a segmental fiat 62 which holdsswitch 56 open, and a uniform radius remainder surface which holds theswitch closed. Both earns 38 and 58 make one revolution during the partof the cycle in which the cubes are ejected and the tray is again filledwith water. As to cam 38, the segments marked A, A, A are all of thesame radius and hold the valve 36 in a position connecting those linestogether to evacuate the space 16 between the liner and tray and directthe air into the bladder 50. The segment marked B reverses the valve andresults in the air being pumped from the bladder into the space 16. Thesegment marked C corresponds to the A positions of the valve (evacuationof the space 16) but with the water fill valve 22 also having a vacuumimposed thereon so that it is opened for charging the tray with water.

The parts in the drawing are shown in their positions corresponding tothe ice in the pockets 18 having been formed, and with the switch 52having just closed in response to a temperature condition indicatingthat the ice cubes are solidly frozen and may be ejected. When theswitch 52 closes, it completes the circuit energizing heater 54 andmotor 26. The initial rotation of shaft and cam 58 closes cycle switch56 to insure that the motor will remain energized for a nearly fullrevolution of the cam even though thermostatic switch 52 opens.

During the initial rotation of the rnotor shaft 40 the control valve 36is positioned in accordance with the A segment of the cam 38. Thisconnects the line 44 to the pump suction line 34 so that the pump 28evacuates the air from the space 16 and pumps it through line 32connected through the valve to line 48 and into the bladder 50. Duringthis A period the linear portions underlying the ice cubes are drawndown away from the surface of the ice cubes to obtain pre-release of theice cubes. Pocket and tray structure for facilitating this pre-releaseis shown in FIGS. 3 and 4 and will be described later. As the cam 38rotates past its initial A position, the cam surface B positions thevalve 36 to connect line 44 to pump discharge line 32, and to connectline 34 to line 48 leading to the bladder 50. Thus air is withdrawn fromthe bladder 50 and pumped into the space 16 underlying the liner toinvert the pockets to the dash-line positions and thus eject the icecubes. Continued rotation of the cam 38 results in the cam surface A"controlling the valve and again reverses the line positions so that thespace 16 is evacuated with the air being pumped into the bladder 50.Thus the pockets 18 are brought back to a water receiving condition.

During the period that the cam surface C controls the valve 36, theconnections through the reversing valve are essentially the same as inthe A positions of the cam with the exception that the line 46 leadingto the fill valve 22 is also connected to line 34 so that the vacuumproduced in line 46 causes the valve 22 to open for a predeterminedperiod to permit the water to be supplied to the pockets. Finally, thecam surface A controls the valve 36 position to continue the vacuumcondition in the space 16 with the water valve closed. As the cam 38approaches its stop position indicated, the cycle switch cam 58 flat 62causes cycle switch 56 to open and terminate the cycle. The thermostaticswitch 52 has of course also opened during the cycle in response to theheat from the heater 54.

Valve 36 may be of a character which permits leakage between the variousports. Thus, changes in atmospheric pressure result in leakage throughthe valve to or from the bladder 50 to compensate therefor without thechanges substantially affecting the positioning of the liner .12. Forexample, a reduction of atmospheric pressure during the period the icecubes are freezing does not result in the pockets moving up toward anejecting position, but rather results in leakage through the valve 36 tocause the bladder 50 to expand instead.

FIG. 2 embodiment In the arrangement of FIG. 2, the system is modifiedto avoid the dependence upon the time required for the thermostaticswitch 52 to operate from a position closed against the cold contact toan open position. Where the parts of FIG. 2 are identical to those ofFIG. 1, identical numerals are used.

The thermostatic switch 52 is provided with both a cold contact 64 and aback (warm) contact 66. The switch 52 may be of the snap-acting bimetaltype.

Two cycle switches 68 and 70 are used instead of the single cycle switchof FIG. 1. Cycle switch 68 has a top contact 72 for connectingelectrical line 74 to motor line 76 when the switch pole is in a topposition, an intermediate contact position 78 in which the switch isopen, and a lower contact position 80 which connects electrical l ne 82(leading to cold contact 64 of switch 52) to motor line 76 when the poleis so positioned.

Cycle switch 70 has a top, open position contact 84 and a lower, closedposition contact 86 which connects line -88 (leading to warm contact 66of switch 52) to motor line 76 when the switch pole is in lowerposition.

Cycle switch 68 is controlled by cam 90 on gear reducer drive shaft 40.The surface of cam 90 'has three levels as illustrated in the drawingwith the outer radius surface holding the switch pole in the top contact72 positron, the middle radius surface dropping the switch pole to theintermediate contact 78 position, and the inner radius surface droppingthe switch pole to the lower contact 80 position.

The second cycle switch 70 is controlled by cam 90 having one surface ofgreater radius holding the switch :70 pole in the top contact 84position in which the switch is open, and another surface of lesserradius closing the switch to the bottom contact 86 position.

In the arrangement shown in FIG. 2 an electrically actuated fill valve94 is used, instead of the pneumatically operated fill valve of FIG. 1.Accordingly, a cam 96 on shaft 40 is used to control a fill valve switch98 which is held in a closed position for a predetermined period duringthe operating cycle to provide a timed water fill of the pockets 18.

The gas pumping system control valve 100 is simplified by elimination ofthe port required to connect the fill valve to a vacuum as in the caseof FIG. 1, and the controll valve opening cam 102 has the C lobe omittedfor the same reason.

The general cycle of operation of the FIG. 2 arrangement is similar tothat of FIG. 1. When a charge of water in the ice tray pockets hasfrozen and the thermostatic switch 52 has cooled sufiiciently, theswitch 52 snaps from the warm contact 66 to the cold contact 64 toinitiate a cycle of ejection and recharge. This energizes the motor 26through line 82, switch 68 in its lower contact 80 position and motorline 76. Heater 54 is simultaneously energized. Switch 52 remains closedto the cold contact until the heater warms it sufiiciently that it snapsto the warm contact. With the motor 66 energized, the cam 90 I0- tatesto a position of large cam surface radius operating cycle switch 68 tothe top contact 72 position which insures that the motor will remainenergized when thermostatic switch 52 snaps to its warm contactposition.

The control valve 100 controlled by cam 102 functions in substantiallythe same way as the valve of the FIG. 1 arrangement. The space 16 belowthe liner is evacuated during the A segment of cam rotation to obtainprerelease of the ice cubes, then the liner 12 is inverted during the Bsegment, and the space 16 is then again evacuated to return the liner tothe water-receiving condition during the A segment.

After the tray has been evacuated and the pockets filled, cams 90 and 92have rotated to positions in which second cycle switch 70 is closed toits lower contact 86 position, and first cycle switch 68 thereafteropens by dropping to its intermediate contacts 70 position. If thethermostatic switch 52 has not by this time snapped to its warm contact66 position, the motor i deenergized until the switch closes to contact66. If the switch has moved to the contact 66 position the motor is thenenergized through line 88, contact 86, and line 76. The motor thencontinues the remainder of its cycle until deenergized by cam 92reaching its stop position and opening cycle switch 70. Simultaneouslythe pole of first cycle switch 68 drops its contact 80 position. Thesystem is then in a condition to await cube freezing and the subsequentclosing of thermostatic switch to cold contact 64 position to startanother cycle.

It is noted with this arrangement the failure of the thermostatic switch52 to move from its cold contact 64 to its warm contact 66 at the propertime does not restart the cycle, such as would occur if the thermostaticswitch of FIG. 1 was still closed at the end of the cycle.

The showing of an electrically actuated water fill valve 94 with the camoperated actuating switch 98 (instead of the pneumatic fill valve ofFIG. 1) is simply illustrative of a variation in the arrangement and hasno direct functional relation to the dual cycle switches 68 and 70. Thusit will be appreciated that a pneumatically operated valve may be usedin the FIG. 2 arrangement as conveniently as in the FIG. 1 arrangement.

In both arrangements the advantageous pro-release of the cubes beforeejection is available and, in both, the preferred air system, asdistinguished from a liquid system, may be used with the attendantadvantage yielded thereby.

Pre-release of the cubes is promoted with a liner and tray arrangementincluding means for supporting cube portions against movement with theliner as the liner is being drawn away from the cubes. Two arrangementsfor giving this support are shown in FIGS. 3 and 4. In FIG. 3, thecavities of the tray 14 in which the liner pockets 18 loosely nest havea pair of upwardly direct d dimples 19 on each lower side. The pocket inits unstressed, water receiving condition may rest on the crown of thesedimples or be above the crowns. In either case an open space 21 existsbetween the major surface area of the cavity wall and facing pocketwall. When the prerelease suction is applied to the plenum space 16,this suction is communicated to the space 21 and the pocket wall isdrawn into the space 21 starting near the upper periphery of the cube.The cube is supported by the dimples so that most of the pocket wall maybe drawn away from the cube.

In the FIG. 4 arrangement, the liner 12 has channels 23 interconnectingadjacent pockets 18 molded therein. The tray 14 structure underlying thechannels provides support for ice pieces formed in the channels, andthus for the cubes, when the pocket wall is drawn down away from thecube.

More detail as to the FIG. 4 arrangement structure may be found in Learnand Moreland commonly assigned US. patent application Ser. No. 652,866,entitled Ice Cube Maker, filed simultaneously herewith, which alsodiscloses additional information as to the type of material which may beused for the liner, and the order of pressures suitable for operation ofa system according to my invention.

I claim as my invention:

1. An automatic icemaker comprising:

a tray;

a flexible mold liner having ice cube forming pockets therein overlyingsaid tray to define an enclosed space between said liner and tray;

a pumping system connected to said enclosed space;

means for filling said pockets with water to be frozen into ice cubes;

means for operating said pumping system to control pressure conditionsin said space in a sequence of first exhausting from said space to placesaid liner in a water receiving condition and then, after said cubes areformed, exhausting from said space again to draw said liner away fromthe ice cubes formed in said pockets, and then pumping into said spaceto invert said pockets so that said cubes are ejected therefrom.

2. An ice-maker according to claim 1 wherein:

said pumping system comprises a gas system closed to atmosphere andincludes a variable volume storage bladder from which said gas may bedrawn for inverting said liner and to which said gas may be pumpedduring the evacuation of said enclosed space between said liner andtray.

3. An icemaker according to claim 2 wherein:

said water fill means includes a water valve controlled in accordancewith sequencing of said gas pumping system.

4. An icemaker according to claim 3 wherein:

said water valve comprises a gas pressure operated valve.

5. An icemaker according to claim 1 wherein:

said gas pumping system includes a single electric motor and a gas pumpdriven thereby when said motor is energized, cam means driven by saidmotor, and a three-position valve connected to said pump and to saidenclosed space and controlled by said cam means, said th ee way valvehaving a first position for connecting said pump to said enclosed spaceto evacuate said enclosed space, a second position connecting said pumpto said enclosed space for pressurizing said space, and a third positionconnecting said enclosed space to said pump for evacuation andsimultaneously actuating said water fill means.

6. An automatic icemaker comprising:

a tray;

a flexible mold liner having ice cube forming pockets therein overlyingsaid tray to define an enclosed space between said liner and tray;

a pumping system connected to said enclosed space;

means for filling said pockets with water to be frozen into ice cubes;

means for operating said pumping system to control pressure conditionsin said space in a sequence of first exhausting from said space to placesaid liner in a water receiving condition and then, after said 7 8 cubesare formed, exhausting from said space again References Cited t0 draw atleast pOr tiOnS Of Said liner away from the ice cubes formed 1n saidpockets, and then pumping gas into said space to invert said pockets sothat 2,683,359 7/1954 Green 62*72 X said cubes are ejected therefrom;and means for 5 2,770,102 11/ 19156 Roedter X supporting at leastselected portions of said cubes against movement With said liner as saidliner is being ROBERT 0 LEARY Przma'y E mmmer' drawn away from saidcubes. W. E. WAYNER, Assistant Examiner.

